Putting the beams in this was a difficult task. Since I knew the weight may be an issue we stripped all the old asphalt shingles off. We then used ice and water shield and did the whole roof over. I put strapping every 6 feet or so and I put cleats on the bottom.
I use my tractor to lift the beams up, which were 400 pounds each
We rested the beams on the cleats and then used a pulley system to decrease the weight by a 2/3
We then dropped them in from the top
At this point, things are a little rickety because the trusses were so cut apart. Once we got the beams sitting on the post we started Sister all the Joyce with 2 x 12.
We did this a few years ago
But working in the garage was unbearable 90% of the time
It was either too hot or too cold
So then I added 36,000 BTU heater and AC mini splits
Then we insulated the whole thing with spray and insulation. The next step is sheet rock.